Data from: Phylogenetic evidence from freshwater crayfishes that cave adaptation is not an evolutionary dead-end

Caves are perceived as isolated, extreme habitats with a set of uniquely specialized biota, which long ago led to the idea that caves are ‘evolutionary dead-ends.’ This suggests that cave-adapted taxa may be doomed for extinction before they can diversify or transition to a more stable state. However, this hypothesis has not been explicitly tested in a phylogenetic framework with multiple independent cave-dwelling groups. Here we use the freshwater crayfish, a group with dozens of cave-dwelling species in multiple lineages, as a system to test this hypothesis. We consider historical patterns of lineage diversification and habitat transition as well as current patterns of geographic range size. We find that while cave-dwelling lineages have small relative range sizes and rarely transition back to the surface, they exhibit remarkably similar diversification patterns to those of other habitat types and appear to be able to maintain a diversity of lineages through time. This suggests that cave-adaptation is not a ‘dead-end’ for freshwater crayfish, which has positive implications for our understanding of biodiversity and conservation in cave habitats.

洞穴被视为孤立且极端的生境，栖息着一系列独特特化的生物类群，这一特征长期以来催生了"洞穴乃进化死胡同"的学术观点。该观点指出，适应洞穴生活的分类群（cave-adapted taxa）或许在实现物种多样化或过渡至更稳定的生境状态前，便注定走向灭绝。然而，这一假说尚未在包含多个独立穴居类群的系统发育框架（phylogenetic framework）中得到明确检验。本研究以淡水螯虾为研究系统——该类群的多个演化支中存在数十种穴居物种——以此检验该假说。我们综合考量了谱系多样化（lineage diversification）与生境转换（habitat transition）的历史模式，以及当前的地理分布范围（geographic range size）格局。研究结果显示，尽管穴居演化支的相对分布范围较小，且极少能转回地表生境，但它们展现出的多样化模式与其他生境类型的类群极为相似，且似乎能够长期维持各类谱系的多样性。这表明，对于淡水螯虾而言，洞穴适应并非"进化死胡同"，这一发现对于我们理解洞穴生境中的生物多样性与保护工作具有积极意义。